Multiple circuit proportional control system



3 A. s. FITZ GERALD 1,985,562

4 MULTIPLE CIRCUIIT PROPORTIONAL CONTROL SYSTEM, M

Fi'led J1me 27,-1953 2 Sheets-Shet '1 )wavrok 2 WSQ Patented Dec. 25, I F M v I menus ArsNr oi-"rics MULTIPLE CIRCUIT PROPORTIONAL CONTROL SYSTEM Alan Stewart Fits Gerald, Wynnewood, Pa. Application June 2'1, 1933, Serial No. 677,788 new. (or. 175-312) This invention relates to methods of controlling, of such control elements can be provided in a in a coordinated manner, a plurality of electric restricted space, as desired. a load units by means of saturating reactor ar- It is, however a very definite disadvantage of rangements such as, for example, apparatus of such prior systems that the space discharge de- 5 the general type I have described inmy copendvices are "not only expensive in first cost but 5' ing application entitled Magnetic amplifiers, filed have a very. limited life. Thus, them-must be rein the United States Patent Omce June 21, 1933, placed at frequent intervals. Not only does this and bearing Serial No. 676,785. involve the expense of renewal of these devices It is especially adapted to the control of illumibut, in addition, it is necessary frequentlyto test 1 vhating arrangements such as are required in the apparatus so thatworn-out" tubes may be providing spectacular eiiects for theatre stage detected and replaced without involving interpresentations, external decorative lighting and ference with performances. g like purposes. It is, however, not restricted to It is an object of the present invention to prothe control of illumination only and may be used vide a control system which will accomplish, l with advantage for such purposes as the control without the necessity of employing space disof motors driving textile machinery, paper-makcharge devices, all of the objects hitherto achieving equipment, wire and rope-winding devices able, only, where such devices have been used. and similar applications. It is a further object of the invention to provide- The main object of'the invention is to. provide a an improved control system which shall consist means of concentrating, into a relatively compact only of apparatus of well-known, simple and recontrol board, all of the switching and control liable form, which is substantially more durable elements necessary for the control, both severally in its characteristics than any space discharge and in combination, of the intensity of illumidevices hitherto available, and which has a nation of a relatively large number of illumiminimum or mechanical apparatus and moving hating units. parts. 25

When such complex and extensive lighting sys- It is a still further object ofthe invention to tems are controlled by means of switchboards of provide a system having greatflexibility in adapthe usual type, for manual operation directly, tation to diverse requirements and which, at the such switchboards may be many feet in length same time, requires only a very limited number and may. require considerable mobility on the of types of apparatus whereby a high degree of 30 part of the" operator. They may, in many cases, standardization in manufacture is possible. require a number of operators in order to produce It is yet another object of the invention to elaborate lighting effects requiring rapid changprovide a system which does not require polying of illumination. phase powenwhich is not affected by fluctuations In some prior systems, it has been possible to in the supply frequency, and which is more ecoprovide a control panel so compact in dimensions nomical than arrangements involving space disthat all of the control elements for a large stage charge devices, in that no power is consumed in may conveniently be reached by a single operator the heating of electrodes, and in which the cirwithout moving from a stationary position. cults are more simple, in that no cathode heating 40 Equipments of this type, which may resemble an circuits are necessary.

organ console, rather. than an electric switch- The basic feature'of the invention is indicated board, may be situated at a control station lo-- by the following considerations, referring to lightcated in the house or auditorium, whereby the oping control systems of the general type described. erator may directly observe the eflects he is, Space discharge devices oi the grid control type producing. can, as is well-known, readily be controlled by 45 In the case of prior systems, however, this remeans of extremely small amounts of power, repsult has been achieved by making use of the grid resenting, in many cases, very minute fractions control feature of vacuum tubes or space disof a watt. On the other hand, any simple manual charge devices. It is well-known that with such control device, sumciently small so that a large devices relatively large amounts of power may number 01. them may be mounted in a limited be controlled with nicety by applying to the grids space, yet, on the other hand, suflciently large of the space discharge devices, very limited to be conveniently manipulated by the human amounts of power. Obviously, this property hand, can easily control amounts of power exrenders it readily possible to employ control ele-, ceedingseveral voltamperes.

ments of small dimensions. Thus, a largenumber Thereis, therefore, nothing to be gained by the z use. of devices so sensitive that they may be controlled by minute amounts of power. It is, in

many hundred times greater than the minimum power necessary to control, by means of the grid.

a space discharge device, the invention provides a system of control in which the energy furnished by the control device is more efiiciently made use of, and is directly employed to actuate the control system, without the use of a space discharge device as an intermediary.

The control element may consist of any suitable electric translating or variable output alternating current device, either of electro-magnetic or other convenient type. It is preferred to employ a simple electromagnetic device of the form embodying relatively movable primary and secondary windings such as is exemplified by a miniature single-phase induction regulator. With this form of construction, the output is a fixed function of the position of the movable elements. It has also the advantages, as compared with variable resistors and the like, that all windings may be insulated and embedded so as to be immune from atmospheric corrosion, and that sliding or open contacts are avoided.

All of the above devices may readilybe furnished in inexpensive and reliable form capable of indefinitely long life in comparison with space discharge devices.

A featureof the invention consists in the fact that proportional control may be obtained by employing a plurality -of saturating reactors with common excitation. A further feature resides in the use of saturating reactors and rectifiers connected to form a catenated system in accordance with the magnetic amplifying arrangements disclosed in my co-pending application, filed June 21,1933, and bearing Serial No. 678,785.

A further feature consists in the use of an a1 ternative switching arrangement whereby a saturating reactor may be used either in uries or in parallel with a control element,whereby the action may, at will, be made either direct or inverse, without the use of any mechanical reversing gears or motions, such as have hitherto been used in the art. I

A still further feature consists in the employment of a compensating winding on the second stage reactor, as disclosed in my co-pending application cited, whereby the effect of themagnetizingcurrent of the first stage reactor, when no saturating effect is applied thereto, is nullified.

These and other novel features which I believe to be characteristic of my invention will be set forth with particularity in the appended claims. My invention itself, however. both. as to its organization and method of operation, together with further objects and advantages thereof, may best beunderstood with reference to the following description takenin connection with the accompanying drawings, in which Figure 1 is a general diagrammatic view of an embodiment of my invention; and

Fig. 2 is a atic view showing, in greater detail, a portion of the embodiment of my invention shown in Fig. 1.

In Fig. 1 I show a typical stage lighting system of the type including grand master" control, color master controls and a further number of individually controllable units.

In Fig. 11 show an illuminating circuit 1 which may be, for example, a footlight, border, or pocket, etc. circuit. The circuit 1 is energized from an alternating current source 2 in series with the reactance winding '3 of a saturating reactor d having a core 5 and direct current saturating winding 6. The winding 6 is supplied with rectified current by means of a rectifier '7. The rectiiier '1 is energized also from the alternating current source 2 and is connected in series with a second saturating-reactor 8 energized through the rectifier 9 from the control element 10 in accordance with the method of connecting saturating reactors and rectifiers in catenation for the purpose of providing an amplifying effect which is shown and described in my co-pending application filed June 21', 1933, bearing Serial No.

The saturating reactor 8 may be similar to the reactor 4 but may be of substantially smaller rating and dimensions. In order to simplify the drawings, the cores of the reactor 8 and other reactors to be later described are omitted, only the windings being indicated. The reactor 8 has a reactance winding 11 which is connected in series with the rectifier 7 and direct current saturating winding 12 energized from the rectifier 9.

The control element 10 has input terminals 16 and output connections 17, the latter being connected to the rectifier 9, as shown. The rectifier 9 may be similar to the rectifier '7, but may be of substantially smaller rating and dimensions. The control element 10, being in eifect a miniature induction regulator, will furnish energy at the output 1'7 which will be proportional to the voltage impressed on the terminals 16 and will vary in accordance with the position of its movable portion which latter may be adjusted by means of the knob 18.

If it be assumed, for the moment, that the terminals-16 of the controlelement 10 are connected to a source of fixed alternating current voltage, the action of the control circuit will be as follows. By movement of the knob 18, the output energy from 10 at the output terminals 1'? may be varied from zero to a maximum. Thus, the energization of the rectifier 9, may be varied in like degree. Accordingly, the rectified current furnished tothe saturating reactor 8 will likewise becontrolled by manual adjustment of the knob 18. The degree of saturation of the reactor 8 will, therefore, be varied and the impedance of the reactance winding 11 will undergo a correspondi'ng'change. This will cause the energiza-. tion of the rectifier '7 to vary in the same way which, in turn, through the saturation of the larger saturating reactor 4, will control the intensity of the illumination of the circuit 1.

The control element 10 is arranged to be energized. by means of a'switch 19,'either directly from the source 2 or, alternatively, in series with a further saturating reactor 20 having saturating winding 21 and the reactance winding 22. The switch 19 has three positions shown as 23, 24, 25. In position 23 the control element is connected directly to the source 2. In position 24 it is disconnected and deenergized. In position 25 the control element is connected in series with the reactance winding 22 of reactor 20 across the source 2. I

degree of saturation of the reactor 20.

Thus, if it is desired to have individual and independent control of the lighting circuit 1, theswitch 19 is placed in position 23. On the other hand, when it is desired to control 1 in accumula-' tion with other units, the whole to be simultaneously controlled as a group unit, the switch 19 is placed at 25. Under this condition, if the position of 10 is such as to give maximum output the .brilliancy of the lights will be controllable from zero to a maximum, in conjunction with other groups according to the saturation of the reactor 20. If, on the other hand, 10 is adjusted to some intermediate'position, the lights will be proportionally controlled, in coordination with the other accumulated units, from zero to an intensity somewhat less than the maximum, corresponding to the position of 10. This proportional dimming feature is an important result achieved by means of the invention.

In a full-size stage equipment, there will, of

course, be a considerable number of lighting cir-- cuits, each controlled by means of individual control elements 10. Three control units are shown in the drawing, but it is to be understood that the invention contemplates any desired number of circuits. For the sake of clearness, and to simplify the drawings, details of the additional circuits have been omitted since these may be identical in arrangement with the one shown,

each consisting of rectifiers 7 and 9, reactors 4 and 8, and the load circuit 1.

An important feature of means for group con.

trol of a number of units which must be considered is the fact that the method of control employed must be operable with an indeterminate number of circuits 1 accumulated into a group.

The system must function in the same mannerwhether only one or two such units are accumulated, or whether substantially all of the units are operated together. The invention provides this feature in the following manner.

Each control unit 10 is provided with an individual control reactor 20, as shown. All of the saturating windings 21 of reactors 20 are connected to form a common circuit. The drawings show these windings connected all in series, but it will be apparent to those skilled in the art that they maybe connected in parallel or in such series-parallel grouping, as may be convenient. Since the drawings only show three control elements 10, whereas a larger number is contemplated, there are shown open connections in the from a rectifier '70.

common circuit of the saturating windings 21.

which may be supposed to represent connections to these additional circuits.

All of the saturating windings 21 are energized This may approximate in order oimagnitudain some cases, to that of the rectifier 7, where there area large number of circuits to be controlled. In other cases, it may be of smaller rating than 7. The rectifier 70 is energized from the source 2 in series with a saturating reactor 80, which may be of the same type as the reactor 8-v having, likewise, a saturating winding 120 and a reactance winding 110. Similarly, the reactor 80 is furnished with saturating current from the rectifier 90 which is controlled by the control element 100. The rectifier 90 may besimilar toil and the joint action of 100, 90, 80 and 70 may be in accordance with the opera tion of 10, 9, 8- and 7. The control element 100 may be identical in construction" with the device l and may, in the general lighting control system, represent what is known as one of the color master" controls. That is to say, the. three control elements 100 may-represent the white, red

and blue color masters, this being a represents.

the reactors 20 in exactly the same manner as the controlelement 10" controls the saturating current of the reactor 4. The operation of 100 will, however, control the alternating current energization of .such of the control elements 10 as may be set with switches 19 in position 25. All elements 10 so connected will be controlled in unison by the color master 100. Such control elements 10 as are connected directly to the source 2 by means of switch 19 being placed in position 23 will-remain entirely unafiected by the operation of the color master.

Such of the circuits 1 as are not required may be set at zero illumination by operating the several switches 19 to position 24. It will be appre ciated that since each control element 10 has an'individual control reactor 20 the action of the group control system willbe entirely unaffected by the number of units'which are accumulated element 100 to the saturating windings 21 is shown, it will be understood that each color master is likewise connected to its appropriate group of color units.

Each of the color masters 100 is energized from the source 2, either directly or in series with in-,

dividual reactors 200, which are similar in functionand may be similar in type to the reactors 20.. A selector switch 190 has the same function and operation as the switch 19 and enables the color masters to be operated individually by direct connection to the source 2 or to be accumulated and controlled simultaneously by the grand masmanner to the collective control of.the control elements 10'by one of the color masters 100, the reactors 200 being excited by a common circuit embracing the saturating windings 210 from a rectifier 900 which may be similar to the rectifiers -9 and 90.

Since, in .general, the color masters will not usually exceed. three or four in number, a single stage -ofrectifier control will probably be sufiicient to furnish the amount of saturating power required. But, it will be obvious to those skilled in the art that, if desired,,a catenated arrange-' ment exactly like the method employed for controlling the control elements 10 from the colormasters 100, embodying reactors 20 and 80, and rectifiers 70 and 90, may be employed.

I have shown in Fig. 1 a general diagrammatic view of an embodiment of my invention showing how' the complete arrangement of individual circuits, color groups, etc. may be controlled either individually, through the color masters, or through the grand master control element.

There may also be included in'the arrangement shown in Fig. 1 various detail features of my inventicn which it is inconvenient, for reasons of space, to show in Fig. 1. These details I show ter 1000. This result isaccomplished in a similar 4 in Fig. 2 which is a diagrammatic view of a portion of the arrangement shown in Fig. 1.

Figure 2 shows detail control arrangements relating to a single circuit, in which the illuminating circuit 1, power source 2, saturating reactor 4, rectifiers '7, 9 and 70, and saturating reactors 8 and 20, are all as shown in Fig. 1.

Special features of my invention which are shown in Fig. 2 are: the method by means of which my invention provides for pre-selection oi illuminating effects whereby the illumination for a subsequent scene can be set up-in advance of the presentation thereof, while the previous scene is in progress; and, the method of producing inverse action whereby one circuit can be increased in intensity, while another circuit may be decreased in intensity, simultaneously, when both are operated from a single group control.

In Figure 2 I show also additional windings 13 and 130 on saturating reactors 4 and 20, respectively. These windings are wound co-axially with the saturating windings 6 and 21, respectively, and are energized with direct current from a source 14, preferably another rectifier. The windings13 and 130 are connected so as to oppose the saturating effect of windings 6 and 21, and the excitation furnished by these windings is arranged to be substantially equal andin opposition to the excitation present in the windings 6 and 21 when there is no saturating effect applied to the saturating reactors 8 and 80, respectively. The windings 13 and 130 are for the purpose of compensating for the magnetizing current of 8 and in accordance with the method described in my copending application, filed June 21, 1933, hearing Serial No. 676,785.

In view of the fact that the embodiment of my invention shown in the drawings requires only two stages of amplification and relates more particularly to the control of illumination, the compensating windings 13 and 130 may, if desired, be omitted. The illumination of most types of electric lamps is reduced substantially to zero when the current in the lamps is reduced to approximately iifty per cent. of the normal rated current. However, the compensating windings provide an increased range or control and may be advantageous in certain instances.

In Figure 2 I have shown the power source 2 having three conductors 201, 202, 203, for the purpose of making available two different -voit-' ages for operating the control system. For example, there may be provided between conductors 201 and 203 the full voltage across which the lighting load is to be operated and which may, for example, be 110 volts, alternating current. Between conductors 201 and 202 I provide a lower voltage, also alternating, which may be or the order of 20 volts.

In view of the fact that my system preferably employs rectifiers oi the contact type, it may be convenient to provide this lower voltage since contact rectifiers can,.at the present time, more readily be procured for such lower voltages.

In modern stage-lighting systems, it is customary to provide what is known as "preselection" of the illumination for one or more entire scenes in advance of any scene actually being presented. On the conclusion of the current scene, the lighting effects for the next scene, which may be of a complex character, and may differ widely from the effects inthe scene which precedes it, may instantly be reproduced, in accordance with prearranged plan, by operating a single switch, known as the all master instead of it being necessary individually to manipulate all or the control elements 10' which are involved. each being adjusted to the intensity required in the next scene. My invention is readily adapted to the provision or this pm-selecting feature. I

In Figure 2 I show the control element 10 and reactors20 in duplicate, and designated 10a, 10b and 20a, 20b,- respectively, in order to provide the pre-selecting feature. As shown in Fig. 2, the output connections 17a and 17b, of the con trol elements 100. and 101), may be connected, alternatively, to the rectifier 9 by means of scenechanging relays 26a and 26b having contacts 27a and 27b, respectively. The operating coiis 28a and 28b of the scene-changing relays are energized, respectively, irom conductors 30. 31A and 30, 313; By means of a selector switch 32 having contacts A and B, as well as an ofi position, energized at will. The switch 32 is known to those skilled in the art as the all master.

Although but a single pair of scene-changing relays 26a and 26?) are shown in the drawings, it is tobe understood that there will be a similar pair for each individual illuminating circuit in the entire system, as indicated by the openeither 31A or 3113 may alternatively be end conductors 30, 31A and 30, 31B, and all of these relays are intended to be simultaneously operated by the switch 32.

Thus, if, in Fig. 2, the switch 32 be closed on contact A, energizing the conductor 31A, scenechanging relay 26a will be energized, closing its ,contact 27a. Thus, the control element 10a is connected to the rectifier 9 and the control element 10b is disconnected. Thus, the illumination of circuit 1 is controlled through the control element 10a, either independently, or by group control, under the color master or the grand master, in accordance with the position of the switches 19, 190.

In a similar manner, if the all-master switch 32 be closed .onto contact B, the circuit 1 will be controlled through control element 10b and 10a will be disconnected.

It will be obvious to those skilled in the art that not only the individual circuit control elements 10 but, in addition, the color masters and even the grand master 1000 as well, may, if desired, be likewise duplicated and pre-selected by means of a like number of additional scenechanging relays 26a and 2612, all operated from the conductors 30, 31A and 31b, and controlled by the all-master switch 32.

It will be further appreciated that more than two scenes may be pre-set if desired, by providing, instead of only two control elements, scenechanging relays, and contacts on the all-master switch 32, three or more, per circuit, as may be required.

In the presentation of illuminating effects of theatre stages and the like, it is frequently required that two or more lighting circuits be controlled in contrary sense. That is, it is desired, simultaneously, to cause one circuit to increase and a second circuit to decrease. Such a requirement, for example, is involved in producing "sunrise and other similar effects. This result is readily brcught about by means of another feature of my invention which I show in I secure the desired reversing action entirely through electrical means.

In Figure 2, the control elements a and 10b :re .each shown capable of being connected to the power source, either directly, for independent control action, or in series with the reactance winding 22 of the saturating reactors 20, when group control is desired, exactly as shown in Fig. 1, by means of switches 19a and 19b.

In Figure 2, I show double pole switches 33a and 33?), whereby the connection of the control elements 10a and 10b may be modified. On referring to Fig. 2 it will be observed that when the double pole switches 33a and 33b are placed in the left-hand position, the connection of the control elements 10a and 10b is as shown in Fig. 1. With this connection, the control will be direct. That is to say, when one of the circuits is accumulated on to one of the color masters,

when the color master is turned so as to increase the energization of the rectifier 90, therectifier 70 and the saturating winding 21 of the reactors 20, the energization of the input terminals 16 of the control element 10 will likewise be increased, and the illumination of the circuit 1 will be increased directly as the color master 100 is increased.

If, on the other hand, the double pole switch.

33 is placed in the right-hand position, the connection of the control elements 10 is modified as follows. Instead of the control elements 10 being energized in series with the reactance winding 22 across the low-voltage supply conductors 201 and 202, the connection is now such that the input terminals 16 of the control elements. 10

are connected in parallel with the reactance winding 22, and the control element and reactance winding, so connected in parallel, are energized from the high.voltage power conductor 201 and 203 in series with an impedance of fixed value 34 which, for example, may be a small choke coil.

Since the control element and reactance winding, in parallel, are now connected across a higher voltage, it will be appreciated that the current drawn from the source conductors 201, 203, will be essentially determined by the impedance 34. In other words, the control element 10 and the reactance winding 22, jointly, will be energized with a substantially constant current. Thus, when the saturating reactor is completely unsaturated and the impedance, represented by the reactance winding 22, is relatively high, the control element 10 will be energized at substantially thesame power input as would be the case when the. terminals 16 are directly connected to the power source conductors 201, 202, through contact 23.

If now, the saturating reactor 20-be saturated by current from the rectifier '70, the impedance of the winding 22 will be lowered and a portion of the current flowing through the choke coil 34 will be diverted from 10,"which will-accordingly be energized to a reduced extent. Whenthe maximum saturating effect is applied to 20 and the impedance of 22 is very low, substantially all 'of the current flowing through 34 flows through 22 and the control element 10 is substantially deenergized.

It will thus be observed that when the switch 33 is placed in the right-hand position, the effect of the color master 100, upon the control element .10 and the circuit 1 thereby controlled, is inverse.

When the color master 100 is increased to a maximum. the illumination of the circuit 1 is decreased substantially'to zero, and. when the color master is-adiusted to a minimum position, the energization of control element 10 and the circuit 1 connected thereto will be a maximum. It will, therefore, be noted that if two different lighting circuits be accumulated on to one of the color masterslOO, and if one of these has the switch 33 placed in the left-hand position, and the second'has the switch 33 placed in the right-hand position, the first-mentioned circuit will be directly controlled by the color master and the second-mentioned circuit will be inversely controlled by the same color master. In other words, as the color master is increased from zero to a maximum,- the first-mentioned circuit will likewise be increased from zero to a maximum, but the secand-mentioned circuit. will be decreased from a' maximum to zero.

It is also to be noted that under both of these conditions, proportional dimming of each individual circuit, through the individual control element 10, is still furnished. If the control element 10 be adjusted so as to give'one-half brilliance, then, when accumulated on to one of the color masters, the intensity of the light, when the color master is varied from zero to amaximum, will either vary from zero to half brilliance or from half brilliance to zero, according to whether the connection is for direct or forinverse action, in accordance with the position of the switch 33.

While I have shown in Fig. 2 the reversingaction by means of the changeover switch 33 applied to an individual lighting circuit, I wish it to be clearly understood that exactly the same con- I the white lights, for example, accumulatedpn to thewhite color master, may be decreased at the same time that all of the red lights, accumulated on to the red color master, may be increased simultaneously at one operation of the grand master 1000.

While my invention is not to be limited to any specific arrangement or to any exact type of size of control elements, rectifiers or reactors, the value and utility of the invention may be better illustrated, if reference be made briefly, to apparatus which was employed in a specific embodiment of the invention which has been studied.

It is well-known to those skilled in the art that saturating reactors of the type generally employed in systems of the general class referred to in this specificatioh'usually require'from two to five per cent. of the power output rating, to be furnished to the saturating winding in order to control the load circuit within the desired limits.- For example, if the circuit 1 represents a 1 kw.

load, the direct current power required to be furnished to the saturating'winding '6 of the reactor 4 will be of the order of watts or less. The output of 7 will, therefore, be about 50 watts and, since the 'eillciency of a rectifier ofthetype contemplated will be approximately 50 per cent, the amount of. alternating current input to be supplied to the rectifier 7 will be in the neighborhood of volt-amperes, which'amount of power the reactor 8 should control.

On this basis, the direct current input tothe reactor 8 would be 5 watts and the alternating current input to the rectifier 9 will be of the order of 10 volt-amperes. ,The control element 10, therefore, should be capable of furnishing an 'al ternating current output variable from zero to 10 the number of control elements 10, which are to be controlled by the color master, the rating of the rectifier '70 may be similar to that of '7; that is to say, it may furnish an output of 50 watts or less,

. as may be necessary. Likewise, the reactor 80 and the rectifier 90 may be similar in rating to the corresponding devices 8 and 9.

Similarly, reactors 200 may be of the same rating as reactors 20 and rectifier 900 similar to 9 and 90.

All of the control elements 10, 100 and 1000 may be of identical construction. I have found that the frame size and core punchings, such as may' be used for the smallest size of fan or fractional horse-power motor, are very suitable for forming the basis of the construction of the control elements. While the torque exerted on the movable element of the control device, when an output of I 10 volt-amperes is drawn from the secondary, can be discerned when manually adjusting the knob 18, it is not such as to impede or substantially affect the action of the device. Suitable locking means, however, such as a friction or serrated rack efiect may, if desired, be employed to ensure that the device remains in the position in which it is placed.. Alternatively, the moving element of the control devices 10, etc. may be operated by means of a worm or other non-overhauling gear.

While the control elements have been referred to as being manually operated, it will be apparent to those skilled in the art that they may also be actuated by suitable mechanical means for the purpose of producing continued slow motion effects such as sunrise, etc. Due to the advanta'ges of the reversing efi'ect embodied in the invention, it is unnecessary to provide the mechanical devices with any reversing gears, such as are required in the more usual arrangements hitherto used. Likewise, duplication of equipment to furnish the reversing feature is not required.

It will be apparent from the foregoing description that the invention is particularly adapted to make use of a very limited number of standard types of apparatus and is, therefore, economical to manufacture, since a high degree of standardization of the various components is readily possible. At the same time, a wide latitude in respect of various circuits and arrangements is possible, the system of control being capable of considerable flexibility in application to varied circuit requirements without involving additional mechanical features of the manufacture of non-standard apparatus.

While the drawingsand description refer to a system of control in three cascaded groups or stages, for example, the grand master, color master and unit control, it will be apparent to those skilled in the art that, without departing from the spirit of the invention, one or more additional cascaded groupings may be provided. For example, in very large installations, in addition to the color masters, there have been used group masters subject to the color master control and controlling, as a group, a plurality of circuits 1. It will be obvious that, if the rectifier '7, in the drawings, be considered to be connected, instead of to the reactor 4, to a plurality of reactors similar to 20, each controlling one of a number of control elements 10 in exactly the manner described above, such additional group requirements will be furnished.

It will equally be apparent to those skilled in the art that, in the case of large amounts of power to be controlled in the manner described, there may be employed, within the scope of the invention, three or more stages of rectifiers and reactors instead of the two-stage arrangement consisting of 7 and 9 and 4 and 8, substantially in accordance with the method described in my cpending application filed June 21, 1933, bearing Serial No. 676,785.

While I have shown and described, by way of example, the method of connecting saturating reactors 20, either in parallel or in series with the control elements as a means of obtaining either direct or inverse control of stage lighting, I wish it to be clearly understood that this feature of my invention is not to be specifically limited to this particular embodiment, but may be used for many other purposes where it is desired to produce two electrical effects varying simultaneously and in opposite sense. For example, means are known to'those skilled in the art whereby, due to a varia-,

tion in the saturating effect applied to a saturating reactor, the phase relation of an alternating current effect, such as, for instance, the voltage applied to the grid of a vapor electric device. may be controlled. It will be obvious to those skilled in the art that, by causing the saturating efiect applied to two saturating reactors, in the manner hereinbefore described, to vary in opposite sense,

one grand master 1000, three duplicate sets of color masters 100, i. e., six in all, three of which may be referred to as 100a and three as 10%. connected exactly as shown in Fig. 1 and each having the reversing arrangement, including switches similar to 33a and 33b, as shown in Fig. 2.

Likewise, for each of the illuminating circuits 1, which the system comprises, there will be duplicate control elements 10a and 10b, exactly as shown in Fig. 2.

It may be assumed that the operator is about to present the first two scenes of a performance.

With the all-master switch 32 set in the ofi position, the operator will proceed to set up all of the control elements designated by the suffix a, both color masters and individual control elements, in accordance with the lighting schedule" for scene one. Any of the color masters which are to be independently controlled will have their switches 190 placed on the upper contacts; those which are to be jointly controlled by the grand to those skilled in the art to which it pertains.

master 1000 will have their switches placed on the lower contacts.

Likewise, all of the individual circuits which are to be independently controlled will be set with the switches 19 on contact 23. Those which are to be group controlled are accumulated on to a color master through contacts 25. Any circuits which are not to be used during the first scene are placed with the switches 19 on contact 24. Each of the control elements 100A and 10A are then turned so as to give exactly the illumination intensity on the various circuits with which the scene is to open. If anyof the circuits are required to be operated inversely,'the switches 33 are thrown to the right. Otherwise, all of the switches 33 are left in the left-hand position. The operator is now prepared for scene one.

The operator then proceeds to make exactly similar adjustments for the second scene. This he does by setting the control elements 1003 and IOB and the switches 190B, 193 and 33b, etc., which are placed in service when the control switch 32 is placed on the lower contact B so as circuit, a plurality of adjustable control elements to energize control circuit 31b.

On receiving the prompt signal for the commencement of scene one, the operator closes the all-master switch 32 on to the upper contact A, energizing conductor 31a and picking up all of the relays 26a, both on the individual circuits and on the color masters. The initial illumination setup, asplanned for the commencement of scene one, is now forthwith presented.

During the presentation of the first scene, the operator may make such changes as may be called for by the action of the performance. Any

. of the individual circuits 1, which are set up for independent control, may be switched on or switched off by the switches 19, as maybe desired, or their intensity may be varied by manipulating the control knobs 18. Likewise, any of the circuits which are accumulated on to a color master may be manipulated as a group by operating the appropriatecolor masters 100 during,

the scene. If some of the circuits 1 are adjusted for inverse operation by throwing the switch 33 to the right, the lighting of these circuits will go up when the color master is turned down, and vice versa. 7

At the conclusion of scene one, all of the circuits automatically become deenergized when the operator opens switch 32 and leaves it in the "off position.

' When the second scene is to be presented, the operator closes switches 32 on to the lower contact B; and, due to the pre-setting of all of the control elements and switches, the desired intensity of all of the various circuits is immediately provided.

The operator makes such changes, during the action of scene two, as is-indicated in precisely ment of my invention for the purpose of explanation, many modifications thereof will be apparent -cept insofar as is necessitated by. the

My invention, therefore, is not to be limited exprior art and-the spirit of the appended claims. What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an allumination control system, a supply circuit, a plurality of adjustable control elements energized from said supply circuit, a plurality of illuminating load circuits each individually controllable by one of said control elements, a further adjustable control element energized from, said supply circuit and means for controlling a plurality of saidilluminating load circuits simultaneously bymeans of said further adjustable control element comprising a plurality of satuenergized from said supply circuit, a, plurality of illuminating load circuits, each individually controllable by one of said control elements through means including a saturable core device subjected to a variable saturating effect derived from one of said control elements and having a winding carrying an alternating current variable in accordance with said saturating effect, rectifying means for rectifying said alternating current, and a second saturable core device subjected to a saturating eiTect due to rectified current deriveddevices cause a variation in the energization of said firstmentioned adjustable control elements. 3. In an illuminationcontrol system, a supply circuit, a plurality of adjustable control elements energized from said supply circuit and furnish ing a variable alternating current output, a plurality of illuminating load circuits each.individually controlled by one of said control elements .through means including rectifying means for rectifying said variable output, a saturable core device subjected to a variable direct current saturating effect derived from one of said control elements and having a winding carrying an alternating current variable in accordance-with said direct current saturating effect, rectifying means for rectifying said alternating current and a second saturable core device subjected to-a direct current saturating efiectdue to rectifiedcurrent derived from the first-mentioned s'aturable'core device, together with a further adjustable control element energized from said supply circuit and furnishing a variable alternating current output, and means for controlling a plurality of said illuminating'loads simultaneously by means of said further adjustable control element com,-

prising rectifying means for rectifying saidvariable output, a plurality of saturable core devices subjected to a direct current saturating effect due S torectifled current derived from said rectifying means, each having a winding carrying an alternating current variable in accordance with said saturating eilect, each of said windings being connected in series with. one of said first-mentioned adjustable control elements whereby the energization of said first-mentioned control elements is varied in accordance with the output or said last-mentioned adlustable control element.

4. In an illumination control system, a plurality of illuminating load circuits, a plurality of individual control means for individually controlling the intensity of the illumination of said circuits, means for controlling a plurality of said illuminating circuits simultaneously, comprising at least one group control element, and a plurality of saturable core devices whereby said group control element controls the energization of a plurality of individual control elements, circuit changing means whereby at least one of said illuminating load circuits may be caused to increase and at least one of said illuminating load circuits may be caused to decrease, in intensity of illumination, simultaneously, when said group control element is operated, comprising means for connecting at least one of said saturable core devices in relation to one 01' said individual control elements so that the energizatlon of said control element is increased when said saturable core device is subjected to increased direct current saturation, and means for connecting at least one of said saturable core. devices in relation to one of said individual control elements so that the energizationot said control element is decreased when said saturable core device is subjected to increased direct current saturation.

5. In an illumination control system, a plu-' rality of illuminating load circuits, a plurality of individual control means for individually controlling the intenslty oi" the illumination of said circuits, means for controlling a plurality of said illuminating circuits simultaneously,comprising at least one group control element, and a plurality of saturable core devices whereby said group control element controls the energization of a plurality of individual control elements, circuit changing means whereby at least one of said illuminating load circuits may be caused to increase and at least one of said illuminating load circuits may he caused to decrease, in intensity of illumination, simultaneously, when said group control element is operated, comprising means for, connecting at least one of said saturable core devices in series with one of said individual control elements-so that the energization of said control element is increased when said saturable core device is subjected to-increased direct current saturation, and means for connecting at least one of said saturable core devices in parallel with one of said individual control elements so that the energize.-

tion of said control element is decreased when said saturable core device is subjected to increased direct current saturation. ,6. In an electric control system, means whereby a numberof power consuming devices may be controlled individually, and means whereby a further number of power consuming devices may be controlled simultaneously, comprising a plurality of saturable core devices, a common direct current saturating circuit embracing all of said saturable core devices, means comprising rectifiers and further saturable core devices whereby the energization of said power consuming devices is controlled, circuit changing means for causing such of said'power consuming devices as are to be controlled simultaneously to be controlled in accordance with the saturating effect applied to said saturable core devices having a common. direct current saturating circuit, and for causing such of said power consuming devices as are to be controlled individually to be controlled independently of said saturable core devices having said common direct current saturating circuit. 1

'7. In an electric system, means for deriving from a varying electric current a second electric current varying in like manner to the first-mentioned current, and a third electric current vary-- ing in opposite sense with respect to the firstmentioned current, comprising a plurality of saturable core devices, means for simultaneously subjecting said devices to like saturating eflects, one of said saturable core devices being connected in series with a circuit element and another of said saturable core devices being energized in parallel with another circuit element, whereby energization of the first-mentioned circuit element is increased, and the energization of the second-mentioned circuit element is decreased, when the saturating efiect applied to said saturable core devices is increased.

8. In an electric system, means for producing a plurality of electrical eflects simultaneously variable in an opposite sense, comprising a. plurality o1 saturable core devices,.means for simultaneously subjecting said devices to like saturating efiects, one of said saturable core devices being connected effectively in series withacircuit element and another of said saturable core devices being energized eflectively in parallel with another circuit element, whereby energizati'on of the first-mentioned circuit element is increased and the energization' of the second'mentioned circuit element is decreased when the saturating eflect applied to said saturable core device is increased. v

9'. In an electric system, means for producing a variation in an electrical effect, and means for producing a second electrical eflect simulta neously variable in an opposite sense comprising a saturablecoredevice having a winding carrying an alternating current, means whereby the first-mentioned electrical eflect causes saturation 01 said saturable core device, a circuit element connected effectively in parallel with said winding, an electric circuit including said winding and said circuit element in parallel, and

, means for maintaining a substantially constant current in said circuit, whereby the energization of said circuit element is increased when said first-mentioned electrical effect is decreased and is decreased when said first-mentioned electrical effect is increased.

. 10. In an electric control system which includes a plurality of power consuming devices each controllable independently through an ampliiying system comprising rectiflers and saturable core devices by an individual control element,-

at least one group control element, and means whereby said group control element may exercise a controlling eflect simultaneously on a predetermined number of said power consuming devices, said controlling eilect being unaffected by the number 01 said power consuming devices controlled simultaneously, and the number ofsaid power consuming devices controlled-independently, comprising a plurality or saturable core devices, having a common saturating circuit,

energized in accordance with the adiultment 0! said group control element, and means whereby each of said saturable core devices causes a variation in the energization of one of said individual control elements.

11. In an illumination control system, a supply circuit, a plurality of saturable core devices each having a saturating winding and an impedance winding, a plurality of adjustable control elements each energized from said supply circuit in series with one of said impedance windings, a plurality of illuminating load circuits each individually controllable by one of said control elements, a-further adjustable control element energized from said supply circuit, a circuit variably energized in accordance with the output of said further adjustable control element, said circuit including all of said saturating windings, whereby'the energization of each of said first mentioned control elements may be varied simultaneously by said second mentioned adjustable control element.

12. In an illumination control system, a supply circuit, a plurality of saturable core devices each having a saturating winding and an impedance winding, a plurality of adjustable control elements each variably energized from said supply circuit in accordance with the impedance of one of said impedance windings, a plurality of illuminating load circuits each individually controllable, through an amplifying system comprising rectiflers and further saturable core devices, by one of said control elements, a further adjustable control element energized from said supply circuit, a circuit variably energized in accordance with the output of said further adjustable control element, said circuit'including all of said saturating windings, whereby the energization of each of said first mentioned controlelements may be varied simultaneously by said second mentioned control element. I

13. In an illumination control system, a supply circuit, a plurality of saturable core devices each having a saturating winding and an impedance winding, a plurality of adjustable control elements each energized from said supply circuit in series with one of said impedance windings, a plurality of illuminating load circuits each individually controllable, through an amplifying system comprising rectifiers and further saturable core devices, by one of said control elements, a further adjustable control element energized from said supply circuit, a circuit variably energized in accordance with the output of said further adjustable control element, said circuit including all of said saturating windings, whereby the energization of each of said first mentioned control elements may be varied simultaneously by saidt second mentioned adjustable control elemen a 14. A system for controlling a plurality of illuminating load circuits in which a. predetermined number of saidcircuits may be controlled independently by means of individual control elements and in which a predetermined number of said load circuits may be controlled collectively by means of a group control element, comprising, a supply circuit, a plurality of saturable core devices each having a saturating winding and an I impedance winding, a plurality of adjustable controlelements, a plurality of illuminating load circuits each controllable by one of said control elements, circuit changing means for causing the control elements associated with said load circuits which are to be independently controlled, to be energized directly from said supply circuit, and for causing the control elements associated with said load circuit which are to be collectively controlled, to be each variably energized from said supply circuit in accordance with the impedance of one of said impedance windings, a further adjustable control element energized from said supply circuitfa circuit variably energized in accordance with the output of said further adjustable control element, said circuit including all of said saturating windings, whereby the energization of the control elements associated with said collectively controlled load circuits may be varied simultaneously by said second mentioned adjustable control element.

15. A system for controlling a plurality of illuminating load circuits in which a predetermined number of said circuits may be controlled independently by means of individual control elements and in which a predetermined number of said load circuits may be controlled simultaneously by means of a group control element, comprising a supply circuit, a plurality of saturable core devices each having a saturating winding and an impedance winding, a plurality of adjustable control elements, a plurality of illuminating load circuits each controllable by one of said control elements, a switch associated with each of said control elements, said switch having a first position, in which said control element is energized directly from said supply circuit, and a second position, in which'said control element is energized from said supply circuit in series with one of said impedance windings, a further adjustable control element energized from said supply circuit, a circuit variably energized in accordance with the output of said further adjustable control element, said circuit including all of said saturating windings, whereby, when a predetermined number 01 said switches are placed in said second position, the energization of the control elements associated with said switches may be varied simultaneously by said second mentioned adjustable control element.

16. In an illumination control system, a supply circuit, a plurality of adjustable control elements energized from said supply circuit, a plurality of illuminating load circuits eachindividually controllable by one oi! said control elements, a further adjustable control element energized irom said supply circuit and means for controlling a plurality of said illuminating load circuits simultaneously by means of said further adjustable control element comprising a plurality of saturable core devices, means for applying a variable saturating eilect derived iromsaid further control element to all of said saturable core devices simultaneously, and means whereby said saturable core devices cause a variation in the energization oi. said first-mentioned adjustable control elements, together with a further plurality of adjustable control elements, a plurality of circuit changing means for effectively connecting one of said further adjustable control illuminating load circuits each individually con-l trollable by one of said control elements, a further adjustable control element energized from said'supply circuit and means for controlling a plurality of said illuminating load circuits simul control element comprising a plurality of saturable core devices, means for applying a variable saturating eflect derived from said iurther control element to all 0! said saturable core devices simultaneously, and means whereby said saturable core devices cause a variation in the energimtion of said first-mentioned adjustable control ele-' .ments, at least two. control elements being provided for each control function, together with means for pro-selecting in advance of the pres-' i,css,sea' taneously by means of said further adjustable entation of an illuminatins eflectsthe circuits to be utilized in producing the said elect, the

circuits which are to be controlled individually,-

the circuits to be accumulated under a group control, :said group. controlled circuits which'are to."

be controlled directly, said group controlled circuits which are to be controlled inversely, and the intensity of illumination to be provided by each of said circuits.

ALAN s'rmwsn'r rrrz'onnam, 

